1. Field of the Invention
The present invention relates to a heat pipe, and more specifically, to a long-acting heat pipe and a corresponding manufacturing method.
2. Description of the Related Art
With the operation speed of CPU (central processing unit) of computer increasing continuously, heat generated from the CPU is increased also. Conventional heat-dissipating devices composed of aluminum extruded heat sinks and fans do not satisfy needs of the current CPU. Thus heat pipes with higher thermal conductivity are designed gradually by manufacturers. The heat pipes cooperate with the heat sinks for solving effectively current heat-dissipating problems. However, the heat-conducting speed and the thermal conductivity of the heat pipes are greatly limited by the inner structure and the amount of working fluid thereof. If having excessive working fluid filled thereinto, vapor channel of the heat pipes will be decreased to greatly limit the thermal conductivity thereof. If having less working fluid, the heat pipes are trend to be dried out and damaged. Therefore, the present inventions improve the conventional heat pipes and the corresponding manufacturing methods based upon the above reasons.
A typical heat pipe having a vapor channel and a liquid channel, which is disclosed in TW Patent Publication No. 200720614, includes a metal tube, a capillary, working fluid, and a vapor-liquid two phases shunt board. The capillary is configured for forming at least two chambers spaced to each other in the metal tube. The working fluid is filled in the metal tube. The vapor-liquid two-phases shunt board is arranged on a surface of the capillary arranged in the middle of the metal tube, and the surface of the capillary faces toward the chambers.
However, although the typical heat pipe having the vapor channel and the liquid channel includes the vapor channel and the liquid channel separated from the vapor channel, the vapor channel is formed in the periphery of the liquid channel. If one end of the heat pipe is heated, the vapor flowing direction and the liquid reflowing direction in the heat-absorption part are opposite to those in the heat-dissipation part. Thus the vapor moving upwards and the liquid moving downwards disturb to each other, to decrease the thermal conductivity thereof. Furthermore, the heat pipe transmits the liquid from the heat-dissipation part to the heat-absorption part by the capillary action of the capillary, thus the thermal conductivity thereof will be decreased with increasing the transmitting length.
Furthermore, the method for manufacturing the typical heat pipe, coats the capillary around the shunt board, inserts the above compositive structure into the metal tube, then fills the working fluid into the metal tube, and finally degasses and seals the metal tube. However, the outer diameter of the heat pipe is generally small, thus it is difficult to coat the capillary around the shunt board. It is more difficult to insert the above compositive structure into the metal tube to contact with the inner surface of the metal tube. The typical heat pipe and the corresponding manufacturing method should be improved.